1. Field of the Invention
This invention relates to a borescope apparatus comprising a borescope with an insertion unit having fluid jet ports and a pressurized fluid supply unit for supplying pressurized fluid to the jet ports.
2. Description of the Related Art
A conventional endoscope or borescope includes an insertion unit having flexibility. The insertion unit can be inserted into cavities having various shapes by making use of the flexibility of the insertion unit for observation of the inside. However, there is a limitation on the scope of use. More specifically, since the insertion unit is soft, it can not support its own weight, so that it is impossible to observe a ceiling wall or advance it beyond a large stepped wall. Therefore, the prior art borescope is inconvenient for the observation of wall surfaces of a cavity having a narrow inlet and a wide inner space or inside of an air conditioner duct, and it can not be utilized for these fields. In order to insert the insertion unit of the borescope into a cavity having a narrow inlet and a wide inner space, a hard or semi-hard pipe is utilized as an auxiliary tool. However, since different cavities, into which the borescope insertion unit is to be inserted, have different shapes, a variety of different auxiliary tools are necessary.
U.S. Pat. No. 4,735,501 discloses a borescope in which compressed air is jetted obliquely rearward through a jet port provided in the distal end of the insertion unit, thereby to move the entire unit. Since the jet port is made in the distal end of the insertion unit, it is therefore difficult for the operator to orientate the distal end in a desired direction. The borescope has means for controlling the fluid. However, the U.S. Patent specification is silent as to what structure this means has to improve the operability of the borescope.
If the inside of a cavity having a narrow inlet and a wide inner space is to be inspected with such a usual borescope, an auxiliary tool for assisting the insertion is necessary for the borescope does not have any support for itself. Further, the observation and inspection with the borescope are difficult for the inside of a ceiling of a building, into which the insertion unit has to be inserted upwards against the gravitational force, or a place with a large stepped wall to be cleared by the inserted insertion unit such as the inside of an air conditioner duct.